--- functions may be called with either all positional arguments or all keyword
--- arguments, but not a mixture. This provides convenience but avoids
--- confusions.


(define f
  (fun (x y)
    (- x y)))


(f 3 2)                                 -- result: 1
(f :x 3 :y 2)                           -- result: 1
(f :y 3 :x 2)                           -- result: -1
